The present invention relates to a method of producing coenzyme Q.sub.10.
Recently, coenzyme Q.sub.10 (abbreviated as CoQ.sub.10) has been interested as a raw material for medicines for curing various diseases such as heart diseases, hypertension, tumor, etc. and can be produced by various microorganisms. For example, journal of Fermentation Technology, 47, p. 553 (1969) discloses a method of improving productivity of coenzyme Q by adding as a component of culture medium p-hydroxybenzoic acid (abbreviated as POBA) which is a precursor in a biosynthetic pathway of coenzyme Q.sub.10. However, the method has a defect that the produced coenzyme Q is Q.sub.9 and not Q.sub.10. Coenzyme Q.sub.9 is substantially inactive to human body and hence it does not exhibit the aforementioned desired pharmaceutical effects.
Japanese Patent Application Publication No. 20,396/72 describes a method of producing CoQ.sub.10 by culturing a yeast, genus Candida capable of producing coenzyme Q in a culture medium containing n-alkane and POBA or POBA and acetic acid or its salt. However, the method has a drawback that production of CoQ.sub.10 is limited owing to the feature of using a yeast, genus Candida and to a fact that POBA has generally such a strong bactericidal property to microorganisms that can be used as a food-preservative so that its addition is restricted to 30 mg/l at the most. Therefore, the method has not been a practical industrial method of producing CoQ.sub.10 because a yield of CoQ.sub.10 is still considerably low.
Japanese Patent Application Laid-Open No. 89,086/79 describes a method of producing CoQ.sub.10 by culturing in a culture medium a microorganism capable of producing CoQ.sub.10. However, the method is useful practically only when the microorganism is Paracoccus denitrificance ATCC 19367 Strain, Agrobacterium tsumefaciene ATCC 4452 strain or Rhodotolura rubra ATCC 20258 strain.
Japanese Patent Application No. 65,739/80 and corresponding U.S. application Ser. No. 258,502 and EPC Patent Application No. 81302196.1 invented by Kaneko and Itoh of the inventors of the present application describe a method of producing CoQ.sub.10 by culturing in a culture medium a microorganism capable of producing CoQ.sub.10. However, the method is useful practically only when the microorganism is Aureobasidium sp. No. 14 strain (International deposition No. FERM BP-1) or Trichosporon sp. WY2-2 (International desposition No. FERM BP-2).